Cationic azo dyes with julolidine units, dyeing composition containing them, method of dyeing

Abstract

The present disclosure relates to the use of cationic azo compounds with julolidine units as direct dyes, for the dyeing of keratin fibers, including human keratin fibers, such as the hair. The present disclosure also relates to a dyeing composition for the dyeing of keratin fibers, including human keratin fibers such as the hair, containing at least one cationic direct azo dye with julolidine units, in a suitable dyeing medium. The present disclosure also relates to a method of dyeing of keratin fibers, including human keratin fibers such as the hair, employing the dyeing composition according to the disclosure. The present disclosure also relates to cationic azo compounds with julolidine units.

1. A method for dyeing keratin fibers, comprising:
 applying to the keratin fibers a dyeing composition comprising at least one direct dye chosen from cationic azo compounds with a julolidine unit of formula (I): 
 
       
         
           
           
               
               
           
         
         wherein: 
         A is a cationic aromatic heterocycle chosen from compounds of formulae (IIa), (IIb), and (IIc): 
       
       
         
           
           
               
               
           
         
         wherein: 
         R 1  is chosen from, independently of one another:
 linear and branched, saturated and unsaturated C 1 -C 16  hydrocarbon chains, which optionally form at least one carbon ring with 3 to 7 ring members, optionally condensed with the aromatic ring, optionally substituted, optionally interrupted by at least one group chosen from heteroatom chosen from oxygen, nitrogen and sulphur, and carbonyl groups; wherein R 1  does not contain a nitro, nitroso, peroxide and diazo bond; and wherein R 1  is directly attached to the nitrogen atom, quaternized or not, of the heteroaromatic ring A by means of a carbon atom; 
 
         R 2  is chosen from, independently of one another:
 linear and branched, saturated and unsaturated C 1 -C 16  hydrocarbon chains, which optionally form at least one aromatic or non-aromatic carbon ring, with 3 to 6 ring members, optionally substituted, optionally interrupted by at least one heteroatom or by at least one group bearing at least one heteroatom; 
 hydroxyl groups; 
 C 1 -C 4  alkoxy groups; 
 C 2 -C 4  (poly)hydroxyalkoxy groups; 
 alkoxycarbonyl groups, R 11 O—CO—, wherein R 11  is chosen from C 1 -C 4  alkyl radicals; 
 alkylcarbonyloxy radicals, R 12 CO—O—, wherein R 12  is chosen from C 1 -C 4  alkyl radicals; 
 amino groups and amino groups substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group, wherein the two alkyl radicals optionally form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members optionally bearing another heteroatom identical to or different from nitrogen; 
 alkylcarbonylamino groups, R 13 CO—NR 13 — and R 13 CO—NH—, wherein the radicals R 13 , independently of one another, are chosen from C 1 -C 4  alkyl radicals; 
 carbamoyl groups, (R 14 ) 2 N—CO, wherein the radicals R 14 , independently of one another, which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 ureido groups, (R 15 ) 2 N—CO—NR 16 —, wherein the radicals R 15  and R 16 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 sulphonamide groups, (R 17 ) 2 N—SO 2 —, wherein the radicals R 17 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 alkylsulphonylamino groups, R 18 SO 2 —NR 19 —, wherein the radicals R 18  and R 19 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 guanidinium groups, (R 20 ) 2 N—C(═NH 2 +)—NR 21 −, wherein the radicals R 20  and R 21 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 nitro groups; 
 cyano groups; 
 halogen atoms; 
 
         wherein two radicals R 2 , carried by adjacent carbon atoms optionally form, together with the carbon atom to which each is attached, an aromatic or non-aromatic condensed ring; 
         m is an integer ranging from 0 to 4; 
         e is an integer ranging from 0 to 2; 
         p is an integer ranging from 0 to 1; 
         D is chosen from groups CR 2  and nitrogen atoms; 
         Q is chosen from groups NR 1  and atoms of oxygen and sulphur; 
         bond a from formulae (IIa), (IIb) or (IIc), joins group A to the azo group; 
         when two radicals R 2  carried by two adjacent carbon atoms form an aromatic ring, bond a optionally joins group A to the azo group via said aromatic ring; 
         wherein the electroneutrality of the compounds is provided by at least one anion An − , which may be identical or different, and is cosmetically acceptable; 
         X, Y and Z are optional substituents on the alkyl and aryl rings of the three-ring nucleus; 
         x is an integer ranging from 0 to 2; 
         y is an integer ranging from 0 to 6; and 
         z is an integer ranging from 0 to 6; 
         or their addition salts or their solvates, 
         wherein, in the definitions above, when an alkyl radical or the alkyl part of a radical is substituted, said substituted alkyl comprises at least one substituent chosen from:
 hydroxyl groups, 
 C 1 -C 4  alkoxy groups and C 2 -C 4  (poly)hydroxyalkoxy groups, 
 amino groups and amino groups substituted with at least one C 1 -C 4  alkyl group, which may be identical or different, optionally bearing at least one hydroxyl group, and said alkyl radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members, optionally containing at least one other heteroatom which may or may not be nitrogen; 
 
         wherein, in the definitions above, when an aryl or heteroaryl radical or the aryl or heteroaryl part of a radical is substituted, said substituted aryl or heteroaryl comprises at least one substituent carried by a carbon atom, wherein for the aromatic ring of the three ring nucleus of said julolidine unit said substituent is X, and wherein X or said at least one substituent is chosen from:
 C 1 -C 16  alkyl radicals, optionally substituted with at least one radical chosen from hydroxy, C 1 -C 2  alkoxy, C 2 -C 4  (poly)-hydroxyalkoxy, acylamino, amino substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group, or the two radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 7 ring members, optionally containing another heteroatom identical to or different from nitrogen; 
 halogen atoms; 
 hydroxyl groups; 
 C 1 -C 2  alkoxy radicals; 
 C 2 -C 4  (poly)-hydroxyalkoxy radicals; 
 amino radicals; 
 amino radicals substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group; 
 acylamino radicals, —NR 31 —COR 32 , wherein the radical R 31  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group and the radical R 32  is chosen from C 1 -C 2  alkyl radicals; 
 carbamoyl radicals, (R 33 ) 2 N—CO—, wherein the radicals R 33 , which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group; 
 alkylsulphonylamino radicals, R 34 SO 2 —NR 35 —, wherein the radical R 34  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group, and the radical R 35  is chosen from C 1 -C 4  alkyl radicals and phenyl radicals; 
 aminosulphonyl radicals, (R 36 ) 2 N—SO 2 —, wherein the radicals R 36 , which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group; 
 
         wherein, in the definitions above, when the cyclic or heterocyclic part of a non-aromatic radical is substituted, it comprises at least one substituent carried by a carbon atom, wherein for the non-aromatic rings of the three ring nucleus of said julolidine unit said substituents are Y and Z, and wherein Y and Z or said at least one substituent is chosen from:
 hydroxyl groups, C 1 -C 4  alkoxy and C 2 -C 4  (poly)hydroxyalkoxy radicals, 
 alkylcarbonylamino radicals, (R 41 CO—NR 42 —, wherein the radical R 42  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group, and the radical R 41  is chosen from C 1 -C 2  alkyl radicals and amino radicals substituted with two C 1 -C 4  alkyl groups, which may be identical or different, optionally bearing at least one hydroxyl group, and said alkyl radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members, optionally containing at least one other heteroatom which may or may not be nitrogen; 
 
         wherein for all definitions above, when a ring does not carry the maximum number of substituents, the unsubstituted position or positions then carry a hydrogen atom. 
       
     
     
       2. The method according to  claim 1 , wherein R 1  is chosen from C 1 -C 8  alkyl and hydroxyalkyl groups. 
     
     
       3. The method according to  claim 1 , wherein formulae (IIa), (IIb) and (IIc) comprise two radicals R 2  carried by adjacent carbon atoms, said radicals forming, together with the carbon atom to which each is attached, an aromatic condensed ring, optionally substituted. 
     
     
       4. The method according to  claim 1 , wherein e, m and p have the value 0. 
     
     
       5. The method according to  claim 1 , wherein x is 0, or x is 1 and X is chosen from alkyl, hydroxyl, hydroxyalkyl, alkoxy, amino, alkylamino, dialkylamino, and acylamino groups. 
     
     
       6. The method according to  claim 1 , wherein the compound of formula (I) is chosen from: 
       
         
           
           
               
               
           
         
       
     
     
       7. A method for dyeing keratin fibers, comprising:
 applying to the keratin fibers a dyeing composition comprising at least one direct dye, 
 leaving the composition on the keratin fibers for a waiting time ranging from 3 minutes to 1 hour; and 
 rinsing the keratin fibers, 
 
       wherein said direct dye is chosen from cationic azo compounds with a julolidine unit of formula (I): 
       
         
           
           
               
               
           
         
         wherein: 
         A is a cationic aromatic heterocycle chosen from compounds of formulae (IIa), (IIb), and (IIc): 
       
       
         
           
           
               
               
           
         
         wherein: 
         R 1  is chosen from, independently of one another:
 linear and branched, saturated and unsaturated C 1 -C 16  hydrocarbon chains, which optionally form at least one carbon ring with 3 to 7 ring members, optionally condensed with the aromatic ring, optionally substituted, optionally interrupted by at least one group chosen from heteroatom chosen from oxygen, nitrogen and sulphur, and carbonyl groups; wherein R 1  does not contain a nitro, nitroso, peroxide and diazo bond; and wherein R 1  is directly attached to the nitrogen atom, quaternized or not, of the heteroaromatic ring A by means of a carbon atom; 
 
         R 2  is chosen from, independently of one another:
 linear and branched, saturated and unsaturated C 1 -C 16  hydrocarbon chains, which optionally form at least one aromatic or non-aromatic carbon ring, with 3 to 6 ring members, optionally substituted, optionally interrupted by at least one heteroatom or by at least one group bearing at least one heteroatom; 
 hydroxyl groups; 
 C 1 -C 4  alkoxy groups; 
 C 2 -C 4  (poly)hydroxyalkoxy groups; 
 alkoxycarbonyl groups, R 11 O—CO—, wherein R 11  is chosen from C 1 -C 4  alkyl radicals; 
 alkylcarbonyloxy radicals, R 12 CO—O—, wherein R 12  is chosen from C 1 -C 4  alkyl radicals; 
 amino groups and amino groups substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group, wherein the two alkyl radicals optionally form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members optionally bearing another heteroatom identical to or different from nitrogen; 
 alkylcarbonylamino groups, R 13 CO—NR 13 — and R 13 CO—NH—, wherein the radicals R 13 , independently of one another, are chosen from C 1 -C 4  alkyl radicals; 
 carbamoyl groups, (R 14 ) 2 N—CO, wherein the radicals R 14 , independently of one another, which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 ureido groups, (R 15 ) 2 N—CO—NR 16 —, wherein the radicals R 15  and R 16 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 sulphonamide groups, (R 17 ) 2 N—SO 2 —, wherein the radicals R 17 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 alkylsulphonylamino groups, R 18 SO 2 —NR 19 —, wherein the radicals R 18  and R 19 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 guanidinium groups, (R 20 ) 2 N—C(═NH 2 +)—NR 21 −, wherein the radicals R 20  and R 21 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 nitro groups; 
 cyano groups; 
 halogen atoms; 
 
         wherein two radicals R 2 , carried by adjacent carbon atoms optionally form, together with the carbon atom to which each is attached, an aromatic or non-aromatic condensed ring; 
         m is an integer ranging from 0 to 4; 
         e is an integer ranging from 0 to 2; 
         p is an integer ranging from 0 to 1; 
         D is chosen from groups CR 2  and nitrogen atoms; 
         Q is chosen from groups NR 1  and atoms of oxygen and sulphur; 
         bond a from formulae (IIa), (IIb) or (IIc), joins group A to the azo group; 
         when two radicals R 2  carried by two adjacent carbon atoms form an aromatic ring, bond a optionally joins group A to the azo group via said aromatic ring; 
         wherein the electroneutrality of the compounds is provided by at least one anion An − , which may be identical or different, and is cosmetically acceptable; 
         X, Y and Z are optional substituents on the alkyl and aryl rings of the three-ring nucleus; 
         x is an integer ranging from 0 to 2; 
         y is an integer ranging from 0 to 6; and 
         z is an integer ranging from 0 to 6; 
         or their addition salts or their solvates, 
         wherein, in the definitions above, when an alkyl radical or the alkyl part of a radical is substituted, said substituted alkyl comprises at least one substituent chosen from:
 hydroxyl groups, 
 C 1 -C 4  alkoxy groups and C 2 -C 4  (poly)hydroxyalkoxy groups, 
 amino groups and amino groups substituted with at least one C 1 -C 4  alkyl group, which may be identical or different, optionally bearing at least one hydroxyl group, and said alkyl radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members, optionally containing at least one other heteroatom which may or may not be nitrogen; 
 
         wherein, in the definitions above, when an aryl or heteroaryl radical or the aryl or heteroaryl part of a radical is substituted, said substituted aryl or heteroaryl comprises at least one substituent carried by a carbon atom, wherein for the aromatic ring of the three ring nucleus of said julolidine unit said substituent is X, and wherein X or said at least one substituent is chosen from:
 C 1 -C 16  alkyl radicals, optionally substituted with at least one radical chosen from hydroxy, C 1 -C 2  alkoxy, C 2 -C 4  (poly)-hydroxyalkoxy, acylamino, amino substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group, or the two radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 7 ring members, optionally containing another heteroatom identical to or different from nitrogen; 
 halogen atoms; 
 hydroxyl groups; 
 C 1 -C 2  alkoxy radicals; 
 C 2 -C 4  (poly)-hydroxyalkoxy radicals; 
 amino radicals; 
 amino radicals substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group; 
 acylamino radicals, —NR 31 —COR 32 , wherein the radical R 31  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group and the radical R 32  is chosen from C 1 -C 2  alkyl radicals; 
 carbamoyl radicals, (R 33 ) 2 N—CO—, wherein the radicals R 33 , which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group; 
 alkylsulphonylamino radicals, R 34 SO 2 —NR 35 —, wherein the radical R 34  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group, and the radical R 35  is chosen from C 1 -C 4  alkyl radicals and phenyl radicals; 
 aminosulphonyl radicals, (R 36 ) 2 N—SO 2 —, wherein the radicals R 36 , which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group; 
 
         wherein, in the definitions above, when the cyclic or heterocyclic part of a non-aromatic radical is substituted, it comprises at least one substituent carried by a carbon atom, wherein for the non-aromatic rings of the three ring nucleus of said julolidine unit said substituents are Y and Z, and wherein Y and Z or said at least one substituent is chosen from:
 hydroxyl groups, 
 C 1 -C 4  alkoxy and C 2 -C 4  (poly)hydroxyalkoxy radicals, 
 alkylcarbonylamino radicals, (R 41 CO—NR 42 —, wherein the radical R 42  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group, and the radical R 41  is chosen from C 1 -C 2  alkyl radicals and amino radicals substituted with two C 1 -C 4  alkyl groups, which may be identical or different, optionally bearing at least one hydroxyl group, and said alkyl radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members, optionally containing at least one other heteroatom which may or may not be nitrogen; 
 
         wherein for all definitions above, when a ring does not carry the maximum number of substituents, the unsubstituted position or positions then carry a hydrogen atom. 
       
     
     
       8. The method according to  claim 7 , wherein the composition is left on the keratin fibers for a waiting time ranging from 15 minutes to 45 minutes. 
     
     
       9. A composition for dyeing keratin fibers comprising, in a suitable dyeing medium, at least one direct dye chosen from cationic azo compounds with a julolidine unit of formula (I): 
       
         
           
           
               
               
           
         
         wherein: 
         A is a cationic aromatic heterocycle compound chosen from compounds of formulae (IIa), (IIb), and (IIc): 
       
       
         
           
           
               
               
           
         
         wherein: 
         R 1  is chosen from, independently of one another:
 linear and branched, saturated and unsaturated C 1 -C 16  hydrocarbon chains, which optionally form at least one carbon ring with 3 to 7 ring members, optionally condensed with the aromatic ring, optionally substituted, optionally interrupted by at least one group chosen from heteroatom chosen from oxygen, nitrogen and sulphur, and carbonyl groups; wherein R 1  does not contain a nitro, nitroso, peroxide and diazo bond; and wherein R 1  is directly attached to the nitrogen atom, quaternized or not, of the heteroaromatic ring A by means of a carbon atom; 
 
         R 2  is chosen from, independently of one another:
 linear and branched, saturated and unsaturated C 1 -C 16  hydrocarbon chains, which optionally form at least one aromatic or non-aromatic carbon ring, with 3 to 6 ring members, optionally substituted, optionally interrupted by at least one heteroatom or by at least one group bearing at least one heteroatom; 
 hydroxyl groups; 
 C 1 -C 4  alkoxy groups; 
 C 2 -C 4  (poly)hydroxyalkoxy groups; 
 alkoxycarbonyl groups, R 11 O—CO—, wherein R 11  is chosen from C 1 -C 4  alkyl radicals; 
 alkylcarbonyloxy radicals, R 12 CO—O—, wherein R 12  is chosen from C 1 -C 4  alkyl radicals; 
 amino groups and amino groups substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group, wherein the two alkyl radicals optionally form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members optionally bearing another heteroatom identical to or different from nitrogen; 
 alkylcarbonylamino groups, R 13 CO—NR 13 — and R 13 CO—NH—, wherein the radicals R 13 , independently of one another, are chosen from C 1 -C 4  alkyl radicals; 
 carbamoyl groups, (R 14 ) 2 N—CO, wherein the radicals R 14 , independently of one another, which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 ureido groups, (R 15 ) 2 N—CO—NR 16 —, wherein the radicals R 15  and R 16 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 sulphonamide groups, (R 17 ) 2 N—SO 2 —, wherein the radicals R 17 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 alkylsulphonylamino groups, R 18 SO 2 —NR 19 —, wherein the radicals R 18  and R 19 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 guanidinium groups, (R 20 ) 2 N—C(═NH 2 +)—NR 21 —, wherein the radicals R 20  and R 21 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 nitro groups; 
 cyano groups; 
 halogen atoms; 
 
         wherein two radicals R 2 , carried by adjacent carbon atoms optionally form, together with the carbon atom to which each is attached, an aromatic or non-aromatic condensed ring; 
         m is an integer ranging from 0 to 4; 
         e is an integer ranging from 0 to 2; 
         p is an integer ranging from 0 to 1; 
         D is chosen from groups CR 2  and nitrogen atoms; 
         Q is chosen from groups NR 1  and atoms of oxygen and sulphur; 
         bond a from formulae (IIa), (IIb) or (IIc), joins group A to the azo group; 
         when two radicals R 2  carried by two adjacent carbon atoms form an aromatic ring, bond a optionally joins group A to the azo group via said aromatic ring; 
         wherein the electroneutrality of the compounds is provided by at least one anion An − , which may be identical or different, and are cosmetically acceptable; 
         X, Y and Z are optional substituents on the alkyl and aryl rings of the three-ring nucleus; 
         x is an integer ranging from 0 to 2; 
         y is an integer ranging from 0 to 6; and 
         z is an integer ranging from 0 to 6; 
         or their addition salts or their solvates, 
         wherein, in the definitions above, when an alkyl radical or the alkyl part of a radical is substituted, said substituted alkyl comprises at least one substituent chosen from:
 hydroxyl groups, 
 C 1 -C 4  alkoxy groups and C 2 -C 4  (poly)hydroxyalkoxy groups, 
 amino groups and amino groups substituted with at least one C 1 -C 4  alkyl group, which may be identical or different, optionally bearing at least one hydroxyl group, and said alkyl radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members, optionally containing at least one other heteroatom which may or may not be nitrogen; 
 
         wherein, in the definitions above, when an aryl or heteroaryl radical or the aryl or heteroaryl part of a radical is substituted, said substituted aryl or heteroaryl comprises at least one substituent carried by a carbon atom, wherein for the aromatic ring of the three ring nucleus of said julolidine unit said substituent is X, and wherein X or said at least one substituent is chosen from:
 C 1 -C 16  alkyl radicals, optionally substituted with at least one radical chosen from hydroxy, C 1 -C 2  alkoxy, C 2 -C 4  (poly)-hydroxyalkoxy, acylamino, amino substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group, or the two radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 7 ring members, optionally containing another heteroatom identical to or different from nitrogen; 
 halogen atoms; 
 hydroxyl groups; 
 C 1 -C 2  alkoxy radicals; 
 C 2 -C 4  (poly)-hydroxyalkoxy radicals; 
 amino radicals; 
 amino radicals substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group; 
 acylamino radicals, —NR 31 —COR 32 , wherein the radical R 31  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group and the radical R 32  is chosen from C 1 -C 2  alkyl radicals; 
 carbamoyl radicals, (R 33 ) 2 N—CO—, wherein the radicals R 33 , which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group; 
 alkylsulphonylamino radicals, R 34 SO 2 —NR 35 —, wherein the radical R 34  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group, and the radical R 35  is chosen from C 1 -C 4  alkyl radicals and phenyl radicals; 
 aminosulphonyl radicals, (R 36 ) 2 N—SO 2 —, wherein the radicals R 36 , which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group; 
 
         wherein, in the definitions above, when the cyclic or heterocyclic part of a non-aromatic radical is substituted, it comprises at least one substituent carried by a carbon atom, wherein for the non-aromatic rings of the three ring nucleus of said julolidine unit said substituents are Y and Z, and wherein Y and Z or said at least one substituent is chosen from:
 hydroxyl groups, 
 C 1 -C 4  alkoxy and C 2 -C 4  (poly)hydroxyalkoxy radicals, 
 
         alkylcarbonylamino radicals, (R 41 CO—NR 42 —, wherein the radical R 42  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group, and the radical R 41  is chosen from C 1 -C 2  alkyl radicals and amino radicals substituted with two C 1 -C 4  alkyl groups, which may be identical or different, optionally bearing at least one hydroxyl group, and said alkyl radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members, optionally containing at least one other heteroatom which may or may not be nitrogen, 
         wherein for all definitions above, when a ring does not carry the maximum number of substituents, the unsubstituted position or positions then carry a hydrogen atom. 
       
     
     
       10. The composition according to  claim 9 , wherein the at least one direct dye of formula (I) is present in an amount ranging from 0.001 to 20% by weight relative to the total weight of the composition. 
     
     
       11. The composition according to  claim 10 , wherein the at least one direct dye of formula (I) is present in an amount ranging from 0.01 to 10% by weight relative to the total weight of the composition. 
     
     
       12. The composition according to  claim 9 , further comprising at least one oxidation base chosen from para-phenylenediamines, bis-phenylalkylenediamines, para-aminophenols, ortho-aminophenols, heterocyclic bases and addition salts thereof. 
     
     
       13. The composition according to  claim 12 , wherein the at least one oxidation base is present in an amount ranging from 0.001 to 20% by weight relative to the total weight of the composition. 
     
     
       14. The composition according to  claim 13 , wherein the at least one oxidation base is present in an amount ranging from 0.005 to 6% by weight relative to the total weight of the composition. 
     
     
       15. The composition according to  claim 9 , further comprising at least one coupling agent chosen from meta-phenylenediamines, meta-aminophenols, meta-diphenols, naphthalenic coupling agents, heterocyclic coupling agents and addition salts thereof. 
     
     
       16. The composition according to  claim 15 , wherein the at least one coupling agent is chosen from 1,3-dihydroxy benzene, 1,3-dihydroxy 2-methyl benzene, 4-chloro 1,3-dihydroxy benzene, 2,4-diamino 1-(β-hydroxyethyloxy) benzene, 2-amino 4-(β-hydroxyethylamino) 1-methoxybenzene, 1,3-diamino benzene, 1,3-bis-(2,4-diaminophenoxy) propane, 3-ureido aniline, 3-ureido 1-dimethylamino benzene, sesamol, 1-β-hydroxyethylamino-3,4-methylenedioxybenzene, α-naphthol, 2-methyl-1-naphthol, 6-hydroxy indole, 4-hydroxy indole, 4-hydroxy N-methyl indole, 2-amino-3-hydroxy pyridine, 6-hydroxy benzomorpholine, 3,5-diamino-2,6-dimethoxypyridine, 1-N-(β-hydroxyethyl)amino-3,4-methylene dioxybenzene, 2,6-bis-(β-hydroxyethylamino)toluene and addition salts thereof. 
     
     
       17. The composition according to  claim 15 , wherein the at least one coupling agent is present in an amount ranging from 0.001 to 20% by weight relative to the total weight of the composition. 
     
     
       18. The composition according to  claim 17 , wherein the at least one coupling agent is present in an amount ranging from 0.005 to 6% by weight relative to the total weight of the composition. 
     
     
       19. The composition according to  claim 9 , further comprising at least one additional direct dye different from the compounds of formula (I), chosen from nitro dyes of the neutral, acid or cationic benzene series; neutral, acid or cationic direct azo dyes; quinone direct dyes; neutral, acid or cationic anthraquinone direct dyes; azine direct dyes; triarylmethane direct dyes; tetraazapentamethine direct dyes; indoamino direct dyes; and natural direct dyes. 
     
     
       20. The composition according to  claim 19 , wherein the at least one additional direct dye is present in an amount ranging from 0.001 and 20% by weight relative to the total weight of the composition. 
     
     
       21. The composition according to  claim 20 , wherein the at least one additional direct dye is present in an amount ranging from 0.005 to 10% by weight relative to the total weight of the composition. 
     
     
       22. The composition according to  claim 9 , further comprising at least one oxidizing agent chosen from hydrogen peroxide, urea peroxide, alkali metal bromates, persalts, peracids and oxidase enzymes. 
     
     
       23. The composition according to  claim 22 , wherein the at least one oxidizing agent is hydrogen peroxide. 
     
     
       24. The composition according to  claim 9 , further comprising at least one hydroxylated solvent. 
     
     
       25. The composition according to  claim 24 , wherein the at least one hydroxylated solvent is chosen from ethanol, propylene glycol, glycerol, and mono ethers of polyols. 
     
     
       26. The composition according to  claim 9 , further comprising at least one additive chosen from anionic, cationic, non-ionic, amphoteric, zwitterionic surfactants or mixtures thereof; anionic, cationic, non-ionic, amphoteric, zwitterionic polymers or mixtures thereof; mineral and organic thickening agents; antioxidizing agents; penetrating agents; sequestering agents; perfumes; buffers; dispersants; conditioners; film-forming agents; ceramides; preservatives and opacifiers. 
     
     
       27. The composition according to  claim 26 , wherein the at least one mineral and organic thickening agent is chosen from anionic, cationic, non-ionic and amphoteric associative polymeric thickening agents. 
     
     
       28. The composition according to  claim 26 , wherein the at least one conditioner is chosen from volatile and non-volatile, modified and unmodified silicones. 
     
     
       29. A kit comprising:
 a first compartment comprising a composition comprising at least one direct dye, and 
 a second compartment comprising a composition comprising at least one oxidizing agent, 
 wherein said at least one direct dye is chosen from cationic azo compounds having a julolidine unit of formula (I): 
 
       
         
           
           
               
               
           
         
         wherein: 
         A is a cationic aromatic heterocycle chosen from compounds of formulae (IIa), (IIb), and (IIc): 
       
       
         
           
           
               
               
           
         
         wherein: 
         R 1  is chosen from, independently of one another:
 linear and branched, saturated and unsaturated C 1 -C 16  hydrocarbon chains, which optionally form at least one carbon ring with 3 to 7 ring members, optionally condensed with the aromatic ring, optionally substituted, optionally interrupted by at least one group chosen from heteroatom chosen from oxygen, nitrogen and sulphur, and carbonyl groups; wherein R 1  does not contain a nitro, nitroso, peroxide and diazo bond; and wherein R 1  is directly attached to the nitrogen atom, quaternized or not, of the heteroaromatic ring A by means of a carbon atom; 
 
         R 2  is chosen from, independently of one another:
 linear and branched, saturated and unsaturated C 1 -C 16  hydrocarbon chains, which optionally form at least one aromatic or non-aromatic carbon ring, with 3 to 6 ring members, optionally substituted, optionally interrupted by at least one heteroatom or by at least one group bearing at least one heteroatom; 
 hydroxyl groups; 
 C 1 -C 4  alkoxy groups; 
 C 2 -C 4  (poly)hydroxyalkoxy groups; 
 alkoxycarbonyl groups, R 11 O—CO—, wherein R 11  is chosen from C 1 -C 4  alkyl radicals; 
 alkylcarbonyloxy radicals, R 12 CO—O—, wherein R 12  is chosen from C 1 -C 4  alkyl radicals; 
 amino groups and amino groups substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group, wherein the two alkyl radicals optionally form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members optionally bearing another heteroatom identical to or different from nitrogen; 
 alkylcarbonylamino groups, R 13 CO—NR 13 — and R 13 CO—NH—, wherein the radicals R 13 , independently of one another, are chosen from C 1 -C 4  alkyl radicals; 
 carbamoyl groups, (R 14 ) 2 N—CO, wherein the radicals R 14 , independently of one another, which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 ureido groups, (R 15 ) 2 N—CO—NR 16 —, wherein the radicals R 15  and R 16 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 sulphonamide groups, (R 17 ) 2 N—SO 2 —, wherein the radicals R 17 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 alkylsulphonylamino groups, R 18 SO 2 —NR 19 —, wherein the radicals R 18  and R 19 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 guanidinium groups, (R 20 ) 2 N—C(═NH 2 +)—NR 21 —, wherein the radicals R 20  and R 21 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 nitro groups; 
 cyano groups; 
 halogen atoms; 
 
         wherein two radicals R 2 , carried by adjacent carbon atoms optionally form, together with the carbon atom to which each is attached, an aromatic or non-aromatic condensed ring; 
         m is an integer ranging from 0 to 4; 
         e is an integer ranging from 0 to 2; 
         p is an integer ranging from 0 to 1; 
         D is chosen from groups CR 2  and nitrogen atoms; 
         Q is chosen from groups NR 1  and atoms of oxygen and sulphur; 
         bond a from formulae (IIa), (IIb) or (IIc), joins group A to the azo group; 
         when two radicals R 2  carried by two adjacent carbon atoms form an aromatic ring, bond a optionally joins group A to the azo group via said aromatic ring; 
         wherein the electroneutrality of the compounds is provided by at least one anion An − , which may be identical or different, and is cosmetically acceptable; 
         X, Y and Z are optional substituents on the alkyl and aryl rings of the three-ring nucleus; 
         x is an integer ranging from 0 to 2; 
         y is an integer ranging from 0 to 6; and 
         z is an integer ranging from 0 to 6; 
         or their addition salts or their solvates, 
         wherein, in the definitions above, when an alkyl radical or the alkyl part of a radical is substituted, said substituted alkyl comprises at least one substituent chosen from:
 hydroxyl groups, 
 C 1 -C 4  alkoxy groups and C 2 -C 4  (poly)hydroxyalkoxy groups, 
 amino groups and amino groups substituted with at least one C 1 -C 4  alkyl group, which may be identical or different, optionally bearing at least one hydroxyl group, and said alkyl radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members, optionally containing at least one other heteroatom which may or may not be nitrogen; 
 
         wherein, in the definitions above, when an aryl or heteroaryl radical or the aryl or heteroaryl part of a radical is substituted, said substituted aryl or heteroaryl comprises at least one substituent carried by a carbon atom, wherein for the aromatic ring of the three ring nucleus of said julolidine unit said substituent is X, and wherein X or said at least one substituent is chosen from:
 C 1 -C 16  alkyl radicals, optionally substituted with at least one radical chosen from hydroxy, C 1 -C 2  alkoxy, C 2 -C 4  (poly)-hydroxyalkoxy, acylamino, amino substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group, or the two radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 7 ring members, optionally containing another heteroatom identical to or different from nitrogen; 
 halogen atoms; 
 hydroxyl groups; 
 C 1 -C 2  alkoxy radicals; 
 C 2 -C 4  (poly)-hydroxyalkoxy radicals; 
 amino radicals; 
 amino radicals substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group; 
 acylamino radicals, —NR 31 —COR 32 , wherein the radical R 31  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group and the radical R 32  is chosen from C 1 -C 2  alkyl radicals; 
 carbamoyl radicals, (R 33 ) 2 N—CO—, wherein the radicals R 33 , which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group; 
 alkylsulphonylamino radicals, R 34 SO 2 —NR 35 —, wherein the radical R 34  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group, and the radical R 35  is chosen from C 1 -C 4  alkyl radicals and phenyl radicals; 
 aminosulphonyl radicals, (R 36 ) 2 N—SO 2 —, wherein the radicals R 36 , which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group; 
 
         wherein, in the definitions above, when the cyclic or heterocyclic part of a non-aromatic radical is substituted, it comprises at least one substituent carried by a carbon atom, wherein for the non-aromatic rings of the three ring nucleus of said julolidine unit said substituents are Y and Z, and wherein Y and Z or said at least one substituent is chosen from:
 hydroxyl groups, 
 C 1 -C 4  alkoxy and C 2 -C 4  (poly)hydroxyalkoxy radicals, 
 alkylcarbonylamino radicals, (R 41 CO—NR 42 —, wherein the radical R 42  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group, and the radical R 41  is chosen from C 1 -C 2  alkyl radicals and amino radicals substituted with two C 1 -C 4  alkyl groups, which may be identical or different, optionally bearing at least one hydroxyl group, and said alkyl radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members, optionally containing at least one other heteroatom which may or may not be nitrogen; and 
 
         wherein for all definitions above, when a ring does not carry the maximum number of substituents, the unsubstituted position or positions then carry a hydrogen atom. 
       
     
     
       30. A cationic azo compound having a julolidine unit of formula (I): 
       
         
           
           
               
               
           
         
         wherein: 
         A is a cationic aromatic heterocycle compound chosen from compounds of formulae (IIa), (IIb), and (IIc): 
       
       
         
           
           
               
               
           
         
         wherein: 
         R 1  is chosen from, independently of one another:
 linear and branched, saturated and unsaturated C 1 -C 16  hydrocarbon chains, which optionally form at least one carbon ring with 3 to 7 ring members, optionally condensed with the aromatic ring, optionally substituted, optionally interrupted by at least one group chosen from heteroatom chosen from oxygen, nitrogen and sulphur, and carbonyl groups; wherein R 1  does not contain a nitro, nitroso, peroxide and diazo bond; wherein R 1  is directly attached to the nitrogen atom, quaternized or not, of the heteroaromatic ring A by means of a carbon atom; 
 
         R 2  is chosen from, independently of one another:
 linear and branched, saturated and unsaturated C 1 -C 16  hydrocarbon chains, which optionally form at least one aromatic or non-aromatic carbon ring, with 3 to 6 ring members, optionally substituted, optionally interrupted by at least one heteroatom or by at least one group bearing at least one heteroatom; 
 hydroxyl groups; 
 C 1 -C 4  alkoxy groups; 
 C 2 -C 4  (poly)hydroxyalkoxy groups; 
 alkoxycarbonyl groups, R 11 O—CO—, wherein R 11  is chosen from C 1 -C 4  alkyl radicals; 
 alkylcarbonyloxy radicals, R 12 CO—O—, wherein R 12  is chosen from C 1 -C 4  alkyl radicals; 
 amino groups and amino groups substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group, wherein the two alkyl radicals optionally form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members optionally bearing another heteroatom identical to or different from nitrogen; 
 alkylcarbonylamino groups, R 13 CO—NR 13 — and R 13 CO—NH—, wherein the radicals R 13 , independently of one another, are chosen from C 1 -C 4  alkyl radicals; 
 carbamoyl groups, (R 14 ) 2 N—CO, wherein the radicals R 14 , independently of one another, which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 ureido groups, (R 15 ) 2 N—CO—NR 16 —, wherein the radicals R 15  and R 16 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 sulphonamide groups, (R 17 ) 2 N—SO 2 —, wherein the radicals R 17 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 alkylsulphonylamino groups, R 18 SO 2 —NR 19 —, wherein the radicals R 18  and R 19 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 guanidinium groups, (R 20 ) 2 N—C(═NH 2 +)—NR 21 —, wherein the radicals R 20  and R 21 , independently of one another, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals; 
 nitro groups; 
 cyano groups; 
 halogen atoms; 
 
         wherein two radicals R 2 , carried by adjacent carbon atoms optionally form, together with the carbon atom to which each is attached, an aromatic or non-aromatic condensed ring; 
         m is an integer ranging from 0 to 4; 
         e is an integer ranging from 0 to 2; 
         p is an integer ranging from 0 to 1; 
         D is chosen from groups CR 2  and nitrogen atoms; 
         Q is chosen from groups NR 1  and atoms of oxygen and sulphur; 
         bond a from formulae (IIa), (IIb) or (IIc), joins group A to the azo group; 
         when two radicals R 2  carried by two adjacent carbon atoms form an aromatic ring, bond a optionally joins group A to the azo group via said aromatic ring; 
         wherein the electroneutrality of the compounds is provided by at least one anion An − , which may be identical or different, and are cosmetically acceptable; 
         X, Y and Z are optional substituents on the alkyl and aryl rings of the three-ring nucleus; 
         x is an integer ranging from 0 to 2; 
         y is an integer ranging from 0 to 6; and 
         z is an integer ranging from 0 to 6; 
         or their addition salts or their solvates, 
         wherein, in the definitions above, when an alkyl radical or the alkyl part of a radical is substituted, said substituted alkyl comprises at least one substituent chosen from:
 hydroxyl groups, 
 C 1 -C 4  alkoxy groups and C 2 -C 4  (poly)hydroxyalkoxy groups, 
 amino groups and amino groups substituted with at least one C 1 -C 4  alkyl group, which may be identical or different, optionally bearing at least one hydroxyl group, and said alkyl radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members, optionally containing at least one other heteroatom which may or may not be nitrogen; 
 
         wherein, in the definitions above, when an aryl or heteroaryl radical or the aryl or heteroaryl part of a radical is substituted, said substituted aryl or heteroaryl comprises at least one substituent carried by a carbon atom, wherein for the aromatic ring of the three ring nucleus of said julolidine unit said substituent is X, and wherein X or said at least one substituent is chosen from:
 C 1 -C 16  alkyl radicals, optionally substituted with at least one radical chosen from hydroxy, C 1 -C 2  alkoxy, C 2 -C 4  (poly)-hydroxyalkoxy, acylamino, amino substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group, or the two radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 7 ring members, optionally containing another heteroatom identical to or different from nitrogen; 
 halogen atoms; 
 hydroxyl groups; 
 C 1 -C 2  alkoxy radicals; 
 C 2 -C 4  (poly)-hydroxyalkoxy radicals; 
 amino radicals; 
 amino radicals substituted with one or two C 1 -C 4  alkyl radicals, which may be identical or different, optionally bearing at least one hydroxyl group; 
 acylamino radicals, —NR 31 —COR 32 , wherein the radical R 31  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group and the radical R 32  is chosen from C 1 -C 2  alkyl radicals; 
 carbamoyl radicals, (R 33 ) 2 N—CO—, wherein the radicals R 33 , which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group; 
 alkylsulphonylamino radicals, R 34 SO 2 —NR 35 —, wherein the radical R 34  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group, and the radical R 35  is chosen from C 1 -C 4  alkyl radicals and phenyl radicals; 
 aminosulphonyl radicals, (R 36 ) 2 N—SO 2 —, wherein the radicals R 36 , which may be identical or different, are chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group; 
 
         wherein, in the definitions above, when the cyclic or heterocyclic part of a non-aromatic radical is substituted, it comprises at least one substituent carried by a carbon atom, wherein for the non-aromatic rings of the three ring nucleus of said julolidine unit said substituents are Y and Z, and wherein Y and Z or said at least one substituent is chosen from:
 hydroxyl groups, 
 C 1 -C 4  alkoxy and C 2 -C 4  (poly)hydroxyalkoxy radicals, 
 alkylcarbonylamino radicals, (R 41 CO—NR 42 —, wherein the radical R 42  is chosen from hydrogen atoms and C 1 -C 4  alkyl radicals optionally bearing at least one hydroxyl group, and the radical R 41  is chosen from C 1 -C 2  alkyl radicals and amino radicals substituted with two C 1 -C 4  alkyl groups, which may be identical or different, optionally bearing at least one hydroxyl group, and said alkyl radicals can form, with the nitrogen atom to which they are attached, a heterocycle with 5 or 6 ring members, optionally containing at least one other heteroatom which may or may not be nitrogen; and 
 
         wherein for all definitions above, when a ring does not carry the maximum number of substituents, the unsubstituted position or positions then carry a hydrogen atom, 
         with the exception of 
         2-(9-julolidylazo)-3-methylbenzothiazolium perchlorate 
         2-(9-julolidylazo)-3-ethylthiazolium perchlorate. 
       
     
     
       31. The compound according to  claim 30 , wherein R 1  is chosen from C 1 -C 8  alkyl and hydroxyalkyl groups. 
     
     
       32. The compound according to  claim 30 , wherein formulae (IIa), (IIb) and (IIc) comprise two radicals R 2  carried by adjacent carbon atoms, said radicals forming, together with the carbon atom to which each is attached, an aromatic condensed ring, optionally substituted. 
     
     
       33. The compound according to  claim 30 , wherein e, m and p have the value 0. 
     
     
       34. The compound according to  claim 30 , wherein x is 0, or x is 1 and X is chosen from alkyl, hydroxyl, hydroxyalkyl, alkoxy, amino, alkylamino, dialkylamino, and acylamino groups. 
     
     
       35. The compound according to  claim 30 , wherein the compound of formula (I) is chosen from: